MECHANICAL PARADOXES. 



striking the air so much more forcibly than on 

 the left, the right-hand side of the boomerang 

 has the stronger tendency to rise, and does 

 rise more than the left-hand end. But it is 

 a curious and striking law of gyroscopic action 

 that when an external force twists in one 

 direction the plane in which a body is spinning, 

 the spinning forces in the body itself resist 



FlQ. 16.-VARIATIONS IN FLIGHT OF BOOMERANG. 



the simple change and insist on a compromise 

 depending on the direction of the spin. 



In the case under our consideration this 

 law operates so that whereas the greater 

 raising effect of the oblique vanes cutting the 

 air more forcibly on the right tends to raise 

 the right side of the boomerang, the additional 

 gyroscopic effect of this twisting the plane of 

 rotation upwards on the right is to twist it 

 upwards also at the front ; and the resulting 



58 



